From e9f4dfe6fbe2a2ab85974180e691af304c49da75 Mon Sep 17 00:00:00 2001
From: Tamas Berghammer <tberghammer@google.com>
Date: Fri, 13 Mar 2015 10:32:42 +0000
Subject: [PATCH] Fix fetching the architecture of the target on process launch

Previously it was fetched only if the architecture isn't valid, but the
architecture can be valid without containing all information about the
current target (e.g. missing os).

Differential revision: http://reviews.llvm.org/D8057

llvm-svn: 232153
---
 lldb/include/lldb/Target/Target.h                  |  3 +++
 .../Process/gdb-remote/ProcessGDBRemote.cpp        | 19 +++++++++--------
 lldb/source/Target/Target.cpp                      | 24 ++++++++++++++++++++++
 3 files changed, 37 insertions(+), 9 deletions(-)

diff --git a/lldb/include/lldb/Target/Target.h b/lldb/include/lldb/Target/Target.h
index 6785c3e..426f038 100644
--- a/lldb/include/lldb/Target/Target.h
+++ b/lldb/include/lldb/Target/Target.h
@@ -1071,6 +1071,9 @@ public:
     bool
     SetArchitecture (const ArchSpec &arch_spec);
 
+    bool
+    MergeArchitecture (const ArchSpec &arch_spec);
+
     Debugger &
     GetDebugger ()
     {
diff --git a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
index 67dcfad..365180a 100644
--- a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
@@ -939,16 +939,17 @@ ProcessGDBRemote::DoLaunch (Module *exe_module, ProcessLaunchInfo &launch_info)
 
             if (m_gdb_comm.SendPacketAndWaitForResponse("?", 1, m_last_stop_packet, false) == GDBRemoteCommunication::PacketResult::Success)
             {
-                if (!m_target.GetArchitecture().IsValid()) 
+                const ArchSpec &process_arch = m_gdb_comm.GetProcessArchitecture();
+
+                if (process_arch.IsValid())
                 {
-                    if (m_gdb_comm.GetProcessArchitecture().IsValid())
-                    {
-                        m_target.SetArchitecture(m_gdb_comm.GetProcessArchitecture());
-                    }
-                    else
-                    {
-                        m_target.SetArchitecture(m_gdb_comm.GetHostArchitecture());
-                    }
+                    m_target.MergeArchitecture(process_arch);
+                }
+                else
+                {
+                    const ArchSpec &host_arch = m_gdb_comm.GetHostArchitecture();
+                    if (host_arch.IsValid())
+                        m_target.MergeArchitecture(host_arch);
                 }
 
                 SetPrivateState (SetThreadStopInfo (m_last_stop_packet));
diff --git a/lldb/source/Target/Target.cpp b/lldb/source/Target/Target.cpp
index 823fba0..beca403 100644
--- a/lldb/source/Target/Target.cpp
+++ b/lldb/source/Target/Target.cpp
@@ -1189,6 +1189,30 @@ Target::SetArchitecture (const ArchSpec &arch_spec)
     return false;
 }
 
+bool
+Target::MergeArchitecture (const ArchSpec &arch_spec)
+{
+    if (arch_spec.IsValid())
+    {
+        if (m_arch.IsCompatibleMatch(arch_spec))
+        {
+            // The current target arch is compatible with "arch_spec", see if we
+            // can improve our current architecture using bits from "arch_spec"
+
+            // Merge bits from arch_spec into "merged_arch" and set our architecture
+            ArchSpec merged_arch (m_arch);
+            merged_arch.MergeFrom (arch_spec);
+            return SetArchitecture(merged_arch);
+        }
+        else
+        {
+            // The new architecture is different, we just need to replace it
+            return SetArchitecture(arch_spec);
+        }
+    }
+    return false;
+}
+
 void
 Target::WillClearList (const ModuleList& module_list)
 {
-- 
2.7.4